Photos (top): A mule is packed with food and other goods for delivery to inhabitants of the Supai, AZ, village at the bottom of the Grand Canyon. Bottom: Leadville, CO, City Carrier Leonard Ortega delivers mail from the Post Office at the highest elevation in the United States.

Go to extremes with this month's edition of Your Postal Podcast, on a whirlwind trip that starts at the Grand Canyon and then travels to the highest and lowest Post Offices in our nation.

We'll also introduce you to new USPS greeting cards designed specifically for sending a salute to everyday heroes. You'll also learn how you can enter to win a free set of Bonsai notecards and stamps.